Machine control switch



Sept 12, 1961 v. R. CARPENTER 2,999,917

MACHINE CONTROL SWITCH Filed Feb. 20, 1959 2 Sheets-Sheet l ,/25 55 aber /36 4V /4 BY wf/M HTC@ NE YS Sept 12, 1961 v. R. CARPENTER 2,999,917

MACHINE CONTROL SWITCH Filed Feb. 20, 1959 2 Sheets-Sheet 2 /A/l//fA/'aD l5. 7 Vilac-n. R. CARPENTER United States Patent O 2,999,917 MACHINE CONTROL SWITCH Virgil R. Carpenter, St. Paul, Minn., assignor to The Unipress Company, Minneapolis, Minn., a corporation of Minnesota Filed Feb. 20, 1959, Ser. No. 794,717 7 Claims. (Cl. 200-153) This invention relates to a new and improved apparatus forming a control for various types of power equipment. More particularly this invention relates to apparatus forming a machine control switch that requires the operator to continuously hold the switch in an in position if the machine is to operate.

It is an object of this invention to provide an improved safety control apparatus. A further object of this invention is to provide a new and improved control apparatus for power equipment. A still further object of this invention is to provide a new and improved switch assembly for controlling power machines that require that one hand of the operator remain in contact with the assembly during the time the machine is in operation.

Still an additional object of this invention is to provide a new and improved control switch assembly having a housing for readily removably mounting a micro-switch and providing an insulating member to removably cover the electric leads connected to the micro-switch mounted i-n said housing. It is still an additional object of this invention to provide a new and improved machine control switch that requires the operator to continuously hold one element of said switch in an in position to maintain 'the operation of Jthe driven power device, the release of said element by the operator opening the power line circuit to the power device. An additional object of this invention is to provide a new and improved machine safety control switch that is relatively inexpensive to produce, easy to assemble and easy to repair.

Other and further objects are those inherent in the invention herein illustrated, described in the claims, and will be apparent as the description proceeds.

To the laccomplishment of the `foregoing and related ends, this invention then comprises features hereinafter ully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principles of the invention may be employed.

The invention is illustrated by reference to the drawings in which the corresponding numerals refer to the same parts and in which;

FIGURE l is a plan view of the machine control switch of this invention;

FIGURE 2 is a side sectional View of the machine control switch of FIGURE l, said view being taken along the line and looking in the direction of the arrows 2 2 of FIGURE l, said view also illustrating said switch mounted on a switch panel;

FIGURE 3 is Aa top view of the machine control switch of this invention mounted on a switch panel, the control member and the insulation element being shown in position for removing the micro-switch from the housing;

FIGURE 4 is `a side sectional view of the machine control switch as illustrated in FIGURE 3, said view being taken along the line and looking in the direction of the arrows 4-4 of FIGURE 3;

FIGURE 5 is an end sectional view of the machine control switch of this invention illustrating the mounting of the micro-switch in the housing, said view being taken along the line and looking in the direction of the arrows 5-5 of FIGURE 2;

FIGURE 6 is an enlarged fragmentary sectional view Patented Sept. 12, 1961 lpCe 2 illustrating the means for operating the micro-switch, the micro-switch actuator ann being sho-wn in an o position in full line and looking in the direction of the arrows 6- 6 of FIGURE l;

FIGURE 7 is an enlarged fragmentary top view of the means for retaining the insulation and the micro switch mounting screws in position in the housing, said view Ibeing taken along the line and looking in the direction of the arrows 7-7 of FIGURE 5.

Referring now to the drawings and in particular to FIGURES 2 and 3 there is shown a side sectional view and a top view of the machine control switch of this invention, said switch being generally designated 10. The machine control switch includes a rectangular, box-shaped housing 11 which has a pair of end walls 12, 13, side walls 14, and a bottom wall 15, said walls. being integrally connected to form a rectangular box-like chamber having an open top. A perimetric flange '16 is formed integral with the top edges of the side and end walls to extend in a direction generally perpendicular to said walls. A pair of apertures 17 are provided in the flange =16 for mounting the machine control switch on appropriate structure, said apertures being located on opposite sides of the housing.

A micro-control switch 22 having dimensions substantially smaller than those of the housing 11 is mounted in the housing with one of the longer sides parallel to and spaced a short distance from the end wall 12, said switch being `attached to the housing by a pair of spaced, round headed screws 23 which extend through appropriate apertures formed in the micro-switch, the insulating member 26, the bottom wall 15 and the tinnermans 29 which retain vthe screws in the bottom wall aperture. The aforementioned insulation member 26 which in part is mounted between the bottom wall 15 and the micro switch will be 'fully described hereinafter.

A rectangular opening 24 is formed in the insulating member and in the bottom wall directly beneath the central portion of the micro-switch. In the opening a pair of elongated U-shaped tinnermans 29 are oppositely spaced with one leg of each of the tinnermans extending over the top surface of the insulating member and the other leg extending under the bottom surface of the bottom wall. An enlarged aperture 29b is formed in the top leg of the tinnerman while enlarged apertures 15a :and 26e are formed in the bottom wall and the insulating member respectively. rllhe use of enlarged apertures in combination with a tinnerman facilitates securing the screws 23 in position relative to the bottom when the micro-switch is mounted since the edges of the aperture do not have to be directly aligned with the micro-switch apertures 22a. The projections 29a on the tinnerman firmly retain the screws 23 in place. By using the tinnerman, the insulating member is held in position in the housing even though the screws 23 have been removed to remove the micro-switch from the housing 11.

The insulating member 26 is a generally rectangular semi-rigid, bendable, iiber sheet which is bent into three sections, 26a, 26b, and 26C. The end section 26a approximates the size and shape of the bottom wall of the micro-switch and has the rectangular aperture 26f formed therein. When the insulating member is mounted in the housing, the central section 26b extends upwardly in an inclined plane from the micro switch to the mid-portion of the end wall 13 and then is reversely bent to form the cover section which extends in a generally horizontal plane to overhang a substantial portion of the microswitch. An angle bracket 36 having an inwardly extending horizontal leg 36a is secured to the mid portion of the end wall 13 so that it is spaced above the bottom wall and forms a stop under which the juncture of the cover member is retained under normal operation conditions. Notches 26d are cut out of the opposite sides of the insulating member at the line of juncture of the ,cover section and the inclined section. The width of the insulating member is substantially equal to the length of the micro-switch. A plurality of spaced terminals-32 as seen in FIGURE 3 extend outwardly from the side wall of the micro-,switch 'which is most closely vadjacentthe end wall 12. A lead aperture 45, see FIGURE l, is formed in the bottom wall 15 intermediate the micro-switch and the end wall 13. Also a rectangular slot 30 is formed in the inclined portion of the insulating member. The lead aperture and rectangular slot permit electric leads 34 to be extended upwardly through the bottom wall aperture 45 and thenv through the insulating member slot 30 where they branch out and are connected to the terminals 32. Thus it may be seen in FIGURE 2 that under normal operating conditions the bare end wire portion 35 of the leads 34 and the terminals 32 are disposed between the cover section 26o and the inclined section 2Gb of the insulating member.

A pivot bolt 38, on which an actuator 39 and a cover or control member 50 are pivotally mounted, extends transversely across the housing 11 through appropriate apertures formed in the housings side walls and is re' tained in position by a tinnerman nut 44. The pivotal axis of the bolt lies within close proximity of a vertical plane passed through the micro-switch side wall which is adjacent to the end wall 12 and at an elevation intermediate the top of the micro-switch housing and the perimetric ange 16. The actuator 39 includes a sleeve 42, a lever arm 40 extending outwardly and generally tangentially to said sleeve portion, and a depending arm 41 which forms an angle of slightly less than 90 with the lever arm. 'I'he lever arm retains the portion 26e of the insulation board intermediate said arm and the terminal 32 even though the cover is in an open position. The depending arm extends downwardly from the pivot bolt to an elevation lower than the push button 33 and adjacent to said push button. An aperture is punched in the lower end of the arm so as to form'the annular ange 41a which projects outwardly from the plane of saidarm. The annular flange forms a set for retaining the coil spring 43 in compression between the arm 41 and the end wall 12. The force of spring 43 rotates the depending arm 41 in the direction of arrow 57 (see FIGURE 2) into engagement with the push button 33 to move said push button to an o position. The amount of rotation of the actuator in the direction of the arrow 57 is limited by the depending arm contacting the micro-switch housing.

Also mounted on the pivot bolt 38 is a rectangular control member 50 which substantially covers the open top of the housing 11. A pair of spaced angular hinge members 51 are formed integral with the control member for pivotally mounting said member, there being a hinge member located on either side of the sleeve 42. A downwardly ex` tending perimetric ilange 52 is also formed integral with the control member to reinforce said member. An inclined offset 54 located intermediate the hinge members and forwardly thereof is formed integral with the control member so that it will bear against the lever arm 40 when the control member is in a closed position. By pushing inwardly on the control member, the offset forces the lever arm to rotate in the direction of arrow 56 which in turn rotates the depending arm in the same direction (from the solid line position to the dotted line position as illustrated in FIGURE 6). Assuming that leads are connected only to terminals C and NO, the aforementioned movement of the depending arm spaces it outwardly from the micro-switch and thereby permits the push button to move in an outward direction to an on position (direction of the arrow 58). The push button is constantly urged to said on position by resilient means (not shown). As the push -button moves in an outward direction it completes a circuit between the ter- "2,999,917 'i Y I i 4 minals 32 (N0 and C) and as a result power is supplied to the electric machine controlled by the switch. Once the operator relieves pressure from the control member 50, the coil spring 43 urges the depending arm to rotate inthe direction of the arrow 57 to force the push button to the normal contact-open position, thus breaking the electric circuit through terminals NO and C and/or, if desired, provide an electric circuit through terminals NC and C if appropriate leads are connected to the last mentioned pair of terminals (as set forth hereinafter).

Another feature of this invention is that due to its shape it may be readily installed to be used for controlling new or existing power equipment setups. For example, the machine switch may be mounted in an appropriate aperture 49 formed in a panel 46 of the power equipment or of a switch mounting structure as follows: After the leads 34 have been connected to terminals 32, the machine control switch may be rotated approximately a quarter of a turn about a horizontal longitudinal axis land twisted to incline the horizontal axis relative to'a horizontal plane so that said switch may be inserted through the panel aperture 49 from below the panel 40. The panel vaperture is of the same similar shape and a little larger than the machine switch with the exception of the perimetric ilange. After the perimetric flange 16 is above the elevation of the panel, the machine control switch is turned and lowered so that the perimetric ange rests on the panel. The switch 10 is then secured in position in the panel aperture by nuts and bolts 48, there being a panel aperture 47 contiguous to each of the flange apertures 17 through which a bolt is inserted.V e e In many industrial establishments power machines are used which can easily injure the limbs of the operator if he should get them in contact with the moving parts of the machine. To alleviate this danger the power supply to the electric machine may be wired so that there are, between the supply and said machine, two of the machine control switches of this invention. If there is to be a completed path through which power is to reach the machine and cause its operation, therefore, both switches must be activated, and this requires continuous pressure on the control members 50 of each switch. Thus if the control switches are properly spaced the operator will have to use both hands to depress the two control members to supply power-*to the machine, and as a consequence the possibility that he will place his limbs in a position to be injured by the moving parts of the machine will be substantially precluded.

As may be noted from FIGURES 3 and 4 the control member may be pivoted to an open position (direction of arrow 57) and thereby substantially open the housing. It can be seen, however, thatl even if the control member is opened, the electric connections to the terminals will not be exposed since they are located beneath the overhanging insulating member portion 26e. 'Ihus in the event that the control member is lifted there is little danger that the operator will get a shock from the electric contacts.

In the event that itis desired to replace the microswitch, the control member may be opened as previously stated. Next the overhanging end portion 26e of the insulating board may be lifted so that it extends substantially parallel to the control member. In lifting said member the inclined portion of the insulating member is moved to rest on the angle bracket 36. Now the screws 23 are exposed.

Upon removing the screws 23, the micro-switch may be readily lifted out of the housing and the insulating member 26 will be held in place by the tinnermans 29. A second micro-switch may be reinserted and mounted in position by the screws 23. Now by pressing the overhanging portion 26C in a downward direction and forcing one edge thereof underneath the angle bracketthe electric leads will be covered. -v In the event the electric leads are to be disconnected from the terminals or the position of said leads changed, the control plate 50 and the insulating member are moved to the aforementioned open position to expose the terminals 32. 'Ihen if, for example, the micro-switch (see FIGURE 3) has one terminal designated by v`"c which is the common terminal, one terminal designated by NO which is the normally open terminal, and one terminal designated by NC which is the normally closed terminal; and if one lead is connected to the terminal C and a second lead is connected to terminal NO, no internal electrical connection is made in the micro-switch between terminals C and NO until the pushbutton is moved in the direction opposite arrow 58. However, if a lead is connected to terminal C and another lead is connected to terminal NO, an internal electrical connection (not shown) is maintained between terminals NO and C as long as the pushbutton is in an index position. As soon as the pushbutton is moved opposite the direction of arrow 58 (from the index position), the internal electrical connection between terminals C and NC is opened and an internal connection closes the internal electric circuit between terminals NO and C. This provision is made for using a machine control switch in an electrical circuit (depending on the terminals to which leads 34 are connected) where it is necessary to depress the control plate 50 to close an electrical circuit to actuate appropriate electrically powered mechanism, or to open an electrical circuit to control electrically powered mechamsm.

As many widely apparent different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to specific embodiments herein.

What I claim is:

1. A machine control switch comprising an open end housing, a cover mounted for limited movement in the open end of said housing, a micro switch mountable in said housing, said micro switch including at least two terminals and a push button to selectively change the electrical relationship between said terminals, an insulating member, and means for independently removably retaining the micro switch in said housing and removably retaining the insulating member in said housing, said insulating member retained in the housing in position for being selectively interposed between the cover and the terminals, said means retaining the micro switch in said housing including a pair of tinnermans for separately retaining the insulating member in the housing, said housing having an elongated aperture through which the tinnermans are extended, and a pair of bolts for removably attaching the micro switch to the tinnermans, one bolt being connected to each tinnerman.

2. A machine control switch comprising a housing having walls joined together to enclose an access opening into the interior of said housing, a micro switch including a plurality of terminals and push button means movably retained in an index position for selectively changing the electrical relationship between said terminals, means for removably securing said micro switch to one wall of the housing within the interior of said housing, a cover plate for closing said access opening, means for pivotally mounting said cover plate on the housing for movement between an index position closing said opening, an open position and a depressed position, means mounted in said housing for transmitting the movement of the cover plate to said depressed position for moving the pushbutton means to change the electrical relationship between said terminals, an insulating member secured in the housing by the means securing the micro switch in the housing, said insulating member having a bent over portion movable between a position interposed between the cover and the terminals to cover the terminals and a position exposing the terminals.

3. The structure of claim 1 further characterized in that the transmitting meansincludes an actuator pivotally mounted in said housing, said actuator having an arm for abutting against the pushbutton means and a second arm within close proximity of the cover plate in a'closed position and that the insulation member is an insulation board.

4. A machine control switch comprising a plurality of walls joined together to enclose an access opening into the interior of the housing, a micro switch mounted within the interior of the housing, said micro switch having a plurality of terminals and a push button movably retained in an indexed position to selectively change the electrical relationship between the terminals, a control plate, means securing said control plate tothe housing for movement between a position to close the access opening, an open position, and a depressed position, actuator me ans for transferring the movement of the control plate to `the depressed position to move the push button to change the electrical relationship between said terminals, and means within the housing for resiliently urging the actuator means to return to an indexed position, said actuator means including an actuator pivotally mounted within said housing, said actuator having a first arm located beneath the control plate and a second arm located between said push button and resilient means, said rst arm being connected Ito the second arm to transfer the movement of the control plate to move the second arm sufliciently to permit the push button to change the electrical relationship between the terminals.

5. A machine control switch comprising a housing having the walls joined together to enclose an access opening into the interior of said housing, a micro switch removably mounted in the interior of the housing, said micro switch including a plurality of terminals and push button means movably retained in an indexed position to selectively changing the electrical relationship between said terminals, a cover plate for closing said access opening, means for pivotally mounting said cover plate on the housing for movement between an indexed position closing said opening, an open position permitting the micro switch to be removed from within the housing and a depressed position, and means mounted on said housing for transferring the movement of the cover plate to said depressed position for moving the push button means to change the electrical relationship between said terminals.

6. The structure of claim 5 further characterized in that transfer means includes an actuator and means for mounting said actuator in the housing to permit removal of the micro switch while the actuator is left mounted in the housing.

7. A machine control switch comprising a housing having walls joined together to enclose an access opening into the interior of the housing, a micro switch mounted in the interior of said housing, said micro switch having a plurality of terminals and' push button means movably retained in an index position for selectively changing the electrical relationship between said terminals, means movably mounted on said housing and within said access opening for engaging the push button means to operate said push button means to change the electrical relationship between the terminals, said push button operating means including a cover plate and means mounting said cover plate on the housing for movement between an index position closing said opening, an open position and a depressed position, and an insulating member attached to the housing for movement from a first position interposed between the push button operating means and the terminals to cover the terminals from exposure through the access opening and a second position exposing the terminals through the access opening, said insulating 8 VReferences Cited in the le of this patent UNITED STATES PATENTS ,Y

A2,849,581Y ningenheimerg; Au'g.26,19ss 5 2,860,212 steam 2 Nov.11,195s

am l, 

